Four Square Metaloop-based Antennas Using C-, N-, and P-metaatoms

Four metaloop antennas (MLAs) are compared to a reference antenna composed of C-type metaatoms. A 2FD-MLA consists of two concentrically arrayed MLAs composed of C-type metaatoms. It is found that the 2FD-MLA has almost the same gain as the reference antenna. A 1FD-MLA, where the two MLAs of the 2FD-MLA are connected and a single feed point is used, is found to have a larger gain than the reference antenna. A 1FD-MLA_N, where the C-type metaatoms constituting the outer metaloop of the 1FD-MLA are replaced with N-type metaatoms, has a gain that is larger for a left-handed circularly polarized wave. In contrast, a 1FD-MLA_P, where C-type metaatoms constituting the inner metaloop of the 1FD-MLA are replaced with P-type metaatoms, has a gain that is larger for a right-handed circularly polarized wave. Some comments are made about the radiation pattern, axial ratio, and VSWR of the antennas.